Richard Anderson (slides based on Rob Jarrett’s slides) The Tablet PC: Designing Pen-based Applications Part II

Back to the Tablet Pen vs. mouse The mouse is better Targeting more accurate Easy to leave in fixed position Integrates well with buttons Cursor positioning is accurate Does not require digitizer The pen is better Superior continuous control Natural device Direct manipulation on screen Does not require auxiliary surface More info than just x-y

Pen as mouse: Targeting Pen motion while hovering Positioning Targeting may require pen to be stationary for a period of time Pushing buttons cause pen tip to move Surface of tablet may be slippery Pressing on screen causes pen to move Tablet may not be stationary

Pen as mouse: Clicking Clicking with a pen is tough Legacy applications typically assume during a click the mouse doesn’t move Pen taps are more like little strokes or stabs because of pen skidding and high-precision digitizers Detecting the difference between tap and a drag is an interesting problem! Double-clicking is even tougher Quick motion means sloppier result

Pen as mouse: Pen positioning Pen positioning can be arduous work if UI requires targeting all over the display Mouse can move the cursor far without much arm/hand movement, but the pen requires a lot of arm/hand movement Menus and toolbars are typically at the top of a window; editing often occurs mid-way or toward the bottom Lots of physical arm/hand movement results – a real pain for users More local UI is desirable (e.g. context menus)

Pen as mouse: Targeting guidelines Cursor feedback Bigger, easily-targeted controls Generous tap, double-click, and hover tolerances Keep related objects in proximity

Pen as mouse: Right-clicking Need to be able to right-click with the pen While not used by majority of Windows users, still an important capability for backwards compatibility and contextual UI Solutions: “Press-and-hold” and pen barrel- button invocation P & H was fairly controversial because some felt it got in the way

Digital ink realism Ink should look smooth No “jaggies” -> antialiased No straight lines -> curve-fitted Use pen pressure information Vary stroke width (more pressure means wider stroke) Support pen tips Round/ballpoint vs. rectangular/ highlighter

Digital ink performance Writing requires uninterrupted inking Users have difficulty with delays in ink appearance Users are frustrated with delays in inking Guideline Ensure fast efficacy Is it as fast as writing on paper?

Pen modes & cursors Explicit vs. implicit input modes A.k.a. Modal vs. modeless How to allow things to be efficient but not confuse users Select mode uses “right-mouse button” for implicit mode as well as utilizing an explicit mode Erase mode uses pen’s eraser tip (if available) for implicit mode as well as utilizing an explicit mode

Pen modes & cursors Need feedback as to the mode of the pen Indicates actions available to the user Guideline Develop a set of cursor feedback to indicate the different modes of the pen Careful attention to cursor design Either symmetric or use handedness setting

Gestures Commands delivered with key strokes Examples Scratch out Keyboard Question Next page Previous page

Pen gestures Gestures need precise tuning Trade-off between accidental activation vs. not getting when wanted False activations are annoying and distracting to the task! Guideline Use gestures guardedly Error on the side of having “zero” incidence of false activation Non-destructive consequences are better

Writing location Users have an initial expectation that they can write digital ink anywhere Guideline Communicate clearly where users can ink Ink enabled controls should be self-evident

Ink selection Traditional rectangular selection tools are inadequate “Lasso” selection is much more natural Percentage-based stroke tolerances Employ word-based selection Visual feedback is essential, real-time is much better than static

Recognition expectations Handwriting recognition is highly variable by person Errors are expected Perceived good or bad handwriting effects expectation of accuracy Guideline Be realistic about recognition accuracy rate, don’t rely heavily on it for authoring

Text input Direct writing with reco Text input area with reco Writing buffer, text buffer, application Special forms of input Stylized letters Gestures (quikwriting) Stylus controlled keyboard Connect a real keyboard

My observations of TPC use Freecell / spider work great Minesweeper fails (difficulty of right click for marking bombs) Inkball is okay Very satisfied with airplane and meeting use

Observations (cont.) Handwriting reco is adequate for text input for short, sentence based input Powerpoint slides Answering Painful for forms entry and longer documents Hard to enter text outside of dictionary

Observations (cont.) I make extensive use of journal See CSE 490ra Winter website for example of Journal notes Useful as a brainstorming / note taking tool I have never converted Journal Notes to text, other than for demo purposes I make frequent misspellings in journal (more than on paper?) Rely on scratch out gesture, not eraser

Observations (cont.) Journal Lasso for selection works well Color/pen selection could be improved Scroll bar is problematic – on HP, I use the page toggle on side Office Tablet PC Pack controls are not very good Pen selection in PPT

Key Frame Animation Given two ink figures, construct a continuous transformation from one to the other

Visualization steering Given a large diagram, how do you control a visualization Static manipulation on multiple scales Time series visualization Strict pen manipulation Domain elevators Large buildings (Sears towers) Time series visualization

Natural UI for Work list Keep track of set of tasks Support control of tasks, annotation, import / export Service technicians application Possible approaches Develop natural metaphor – piles of cards? Direct manipulation interface Pen based NL / diagram interface